Formation degradation, such as asphalt milling, mining, or excavating, may result in wear on attack tools. In excavating operations, often, a trenching machine comprises an array of attack picks disposed within holders that may be rotated and moved so that the attack picks engage a hard surface. Consequently, many efforts have been made to extend the life of these tools.
U.S. Pat. No. 4,274,678 to Herridge, which is herein incorporated by reference for all that it contains, discloses a mineral mining pick boss having a socket therein for the reception of a shank of a mineral mining pick and a locking arrangement for retaining the shank, the locking arrangement comprising a plug received in the bore extending through the boss transversely of the socket the arrangement being such that the bore intersects the socket, the plug comprising a body of a resilient material (e.g. neoprene) having bonded into the periphery thereof at spaced locations a plurality of metallic members one of which protrudes from the bore into the socket for frictional engagement with the shank of the tool so as to retain the tool in position, the other(s) of the metallic members being such that the plug may be removed from the bore, rotated and re-inserted to change the metallic member which protrudes into the socket.
U.S. Pat. No. 5,873,423 to Briese, which is herein incorporated by reference for all that it contains, discloses a frustum cutting bit arrangement, including a shank portion for mounting in, and to be retained by, a rotary cutting tool body, the shank portion having an axis, an inner axial end, and an outer axial end. A head portion has an axis coincident with the shank portion axis, a front axial end, and a rear axial end, the rear end coupled to the shank portion outer end, and the front end having a conical cavity therein diminishing in diameter from the front end toward the rear end. A frustum cutting insert has an axis coincident with the head portion axis, a forward axial end, a back axial end, and an outer conical surface diminishing in diameter from the forward end toward the back end, the conical cavity in a taper lock. In variations of the basic invention, the head portion may be rotatable with respect to the shank portion, the frustum cutting insert may comprise a rotating cutter therein, and combinations of such features may be provided for different applications.
U.S. Pat. No. 5,702,160 to Levankovskii et al., which is herein incorporated by reference for all that it contains discloses a tool for crushing hard material comprising a housing and a hard-alloy insert mounted on the latter. The insert is made up of a head portion, an intermediate portion and a base with a thrust face. The intermediate portion of the insert is formed by a body of revolution with an outer lateral surface of concave shape. The head portion of the insert is formed by a body of revolution with an outer lateral surface of convex shape. The lateral side of the head portion of the insert is smoothly located adjacent to the lateral side of the intermediate portion of the insert about its longitudinal axis does not exceed the length of the head portion of the insert about the same axis.